JP2024043120A - Vehicle control device - Google Patents

Abstract

To prevent a lock-up piston and a turbine hub from wearing against each other.SOLUTION: A vehicle control device comprises: a turbine hub which has a flange section connected to a turbine runner of a torque converter and a hub section connected to a turbine shaft; a lock-up piston which has a cylinder section which is positioned on a peripheral surface of the hub section and slidably supported and a disk section outwardly extended from the cylinder section in a radial direction; a damper mechanism which is connected to both the turbine hub and the lock-up piston; and a control system which controls an engine connected to the torque converter. The control system: calculates a PV value which is a product of sliding surface pressure between the hub section and the cylinder section and a sliding speed; and causes engine torque to change more gradually when the PV value exceeds a threshold compared to when the PV value falls below the threshold.SELECTED DRAWING: Figure 8

Description

The present invention relates to a vehicle control device installed in a vehicle.

A power train installed in a vehicle includes an engine and a torque converter connected to the engine. Further, the torque converter is provided with a lock-up clutch that directly connects the crankshaft on the input side and the turbine shaft on the output side. Furthermore, the torque converter is provided with a damper mechanism that allows relative rotation between the crankshaft and the turbine shaft while the lockup clutch is engaged, that is, a damper mechanism that allows relative rotation between the lockup piston and the turbine hub. (See Patent Documents 1-3).

Japanese Patent Application Publication No. 2015-113904 JP 2011-64291 A JP 2019-44903 Publication

By the way, when the engine torque increases or decreases while the lockup clutch is engaged, the damper mechanism is twisted and the lockup piston and turbine hub rotate relative to each other. At this time, the contact area between the lockup piston and the turbine hub slides against each other, but excessive wear on this contact area causes hydraulic oil circulation within the torque converter, increasing the work of the oil pump. It was a factor. Further, excessive wear of the contact portion between the lockup piston and the turbine hub has been a factor in causing failure in lockup clutch engagement.

An object of the present invention is to suppress wear between a lockup piston and a turbine hub.

A vehicle control device according to one embodiment is a vehicle control device provided in a vehicle, and includes a turbine hub including a flange portion connected to a turbine runner of a torque converter, and a hub portion connected to a turbine shaft. , a lockup piston including a cylindrical portion slidably supported on an outer circumferential surface of the hub portion, and a disk portion extending radially outward from the cylindrical portion; and both the turbine hub and the lockup piston. a control system that controls an engine that is connected to the torque converter and includes a damper mechanism that is connected to the hub portion and allows relative rotation between the hub portion and the cylindrical portion, and a processor and memory that are communicably connected to each other; The control system is a product of a sliding surface pressure and a sliding speed between the hub portion and the cylindrical portion in a state in which the lock-up piston is fastened to the crankshaft of the engine. A PV value is calculated, and when the PV value exceeds a threshold value, the engine torque is changed more gently than when the PV value is less than the threshold value.

According to one aspect of the present invention, the control system is a product of sliding surface pressure and sliding speed between the hub portion and the cylindrical portion under a state in which the lock-up piston is fastened to the crankshaft of the engine. A PV value is calculated, and when the PV value exceeds a threshold value, the engine torque is changed more gently than when the PV value is below the threshold value. Thereby, wear between the lockup piston and the turbine hub can be suppressed.

1 is a diagram showing an example of a vehicle equipped with a vehicle control device according to an embodiment of the present invention; It is a figure showing an example of a control device for vehicles. FIG. 3 is a diagram showing an example of the basic structure of a control unit. FIG. 3 is a diagram showing a torque converter and its vicinity. FIG. 2 is a cross-sectional view showing a torque converter together with a valve body. 5 is a diagram illustrating a part of the lockup damper and the lockup piston along line AA in FIG. 4. FIG. FIG. 3 is a diagram showing an example of an operating state of a lock-up damper. 3 is a flowchart illustrating an example of an execution procedure of wear suppression control. It is a figure which shows an example of the sliding surface pressure estimated based on engine rotation speed and engine torque. 4 is a cross-sectional view showing a sliding portion between a hub portion and a cylindrical portion and the vicinity thereof. FIG. It is a schematic diagram which shows an example of the load input into the sliding part of a hub part and a cylindrical part. 5 is a schematic diagram showing an example of a load input to a sliding portion between a hub portion and a cylindrical portion. FIG. FIG. 3 is a diagram showing an example of the relationship between engine torque and sliding speed. It is a figure which shows an example of the threshold value with which a PV value is compared. FIG. 3 is a diagram showing an example of an execution status of torque change suppression processing. FIG. 7 is a diagram showing another control example in the torque change suppression process.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In the following description, the same or substantially the same configurations and elements will be designated by the same reference numerals and repeated description will be omitted.

[vehicle]
FIG. 1 is a diagram showing an example of a vehicle 11 equipped with a vehicle control device 10 that is an embodiment of the present invention. As shown in FIG. 1, the vehicle 11 is equipped with a power train 14 that includes an engine 12 and a transmission 13. The transmission 13 includes a torque converter 15 and a transmission mechanism 16 such as an automatic transmission or a continuously variable transmission. Further, wheels 20 are connected to the output shaft 17 of the transmission 13 via a propeller shaft 18 and a differential mechanism 19. Although the illustrated power train 14 is a rear-wheel drive power train, it is not limited to this, and may be a front-wheel drive or all-wheel drive power train.

FIG. 2 is a diagram showing an example of the vehicle control device 10. As shown in FIG. 2, the power train 14 is provided with a valve body 21 consisting of an electromagnetic valve, an oil passage, etc. in order to control the torque converter 15, transmission mechanism 16, etc. incorporated in the power train 14. Further, an oil pump 22 driven by the engine 12 is connected to the valve body 21 . Hydraulic oil pumped from the oil pump 22 passes through the valve body 21, is regulated in pressure, and then is supplied to the torque converter 15, transmission mechanism 16, and the like. Further, a mission control unit 23 is connected to the valve body 21 in order to control the torque converter 15 and the like via the valve body 21 .

Further, the intake manifold 24 of the engine 12 is provided with a throttle valve 25 that adjusts the amount of intake air. Further, the engine 12 is provided with an injector 26 that injects fuel into an intake port or into a cylinder, and is provided with an ignition device 27 consisting of an igniter, a spark plug, or the like. An engine control unit 28 is connected to the throttle valve 25, injector 26, ignition device 27, etc. in order to control engine torque and engine speed.

[Control system]
As shown in FIG. 2, the vehicle control device 10 is provided with a control system 30 consisting of a plurality of electronic control units in order to control the power train 14 and the like. As electronic control units constituting the control system 30, the aforementioned mission control unit 23 and engine control unit 28 are provided, and a vehicle control unit 31 that outputs control signals to these control units 23 and 28 is provided. These control units 23, 28, and 31 are communicably connected to each other via an in-vehicle network 29 such as CAN. The vehicle control unit 31 sets operating targets for the engine 12, torque converter 15, etc. based on input information from various control units and various sensors described below. Then, it generates control signals according to operating targets for the engine 12, torque converter 15, etc., and outputs these control signals to the engine control unit 28 and the mission control unit 23.

Sensors connected to the vehicle control unit 31 include a vehicle speed sensor 32 that detects the vehicle speed, which is the traveling speed of the vehicle 11, an accelerator sensor 33 that detects the operation status of the accelerator pedal, and a brake sensor 34 that detects the operation status of the brake pedal. A start switch 35 that is operated by the driver when starting the control system 30 is also connected to the vehicle control unit 31. Furthermore, sensors connected to the engine control unit 28 include a crank angle sensor 37 that detects the rotation angle of the crankshaft 36 provided in the engine 12, an air flow meter 38 that detects the intake air amount of the engine 12, a water temperature sensor 39 that detects the cooling water temperature of the engine 12, and a throttle opening sensor 40 that detects the opening degree of the throttle valve 25. The engine control unit 28 can calculate the engine torque, which is the output torque of the crankshaft 36, based on the detection signals from the various sensors, and can calculate the engine speed, which is the rotation speed of the crankshaft 36.

FIG. 3 is a diagram showing an example of the basic structure of the control units 23, 28, and 31. As shown in FIG. 3, the control units 23, 28, and 31, which are electronic control units, have a microcontroller 52 in which a processor 50, a main memory (memory) 51, and the like are incorporated. A predetermined program is stored in the main memory 51, and the program is executed by the processor 50. Processor 50 and main memory 51 are communicably connected to each other. Note that a plurality of processors 50 may be incorporated into the microcontroller 52, and a plurality of main memories 51 may be incorporated into the microcontroller 52.

Further, the control units 23, 28, 31 are provided with an input circuit 53, a drive circuit 54, a communication circuit 55, an external memory 56, a power supply circuit 57, and the like. The input circuit 53 converts signals input from various sensors into signals that can be input to the microcontroller 52. The drive circuit 54 generates drive signals for various devices such as the above-mentioned injector 26 based on signals output from the microcontroller 52. Communication circuit 55 converts signals output from microcontroller 52 into communication signals directed to other control units. The communication circuit 55 also converts communication signals received from other control units into signals that can be input to the microcontroller 52. Further, the power supply circuit 57 supplies a stable power supply voltage to the microcontroller 52, input circuit 53, drive circuit 54, communication circuit 55, external memory 56, and the like. Additionally, programs and various data are stored in an external memory 56 made of non-volatile memory or the like.

[Torque converter]
Fig. 4 is a diagram showing the torque converter 15 and its vicinity, and Fig. 5 is a cross-sectional view showing the torque converter 15 together with the valve body 21. Note that Fig. 5 shows a part of the valve body 21 and a part of the torque converter 15.

As shown in FIGS. 4 and 5, torque converter 15 has a pump shell 60 connected to engine 12. As shown in FIGS. That is, the pump shell 60 is connected to the crankshaft 36 of the engine 12 via the drive plate 61. The torque converter 15 also includes a pump impeller 62 fixed to the pump shell 60 and a turbine runner 63 facing the pump impeller 62. A flange portion 65 of a turbine hub 64 is connected to the turbine runner 63, and a turbine shaft 67 is connected to a hub portion 66 of the turbine hub 64. Hydraulic oil is supplied to the torque converter 15, and engine torque is transmitted from the pump impeller 62 to the turbine runner 63 via the hydraulic oil. Note that the transmission mechanism 16 is connected to the turbine shaft 67, and the oil pump 22 is connected to the pump shell 60 via a chain mechanism 68.

[Lockup clutch]
The torque converter 15 is provided with a lock-up clutch 70 that directly connects the crankshaft 36 and the turbine shaft 67. Lockup clutch 70 has a lockup piston 71 housed in pump shell 60. This lock-up piston 71 faces a front cover 72 of the pump shell 60. The lockup piston 71 also includes a cylindrical portion 73 that is slidably supported on the outer circumferential surface 66a of the hub portion 66 of the turbine hub 64, and a disk portion 74 that extends radially outward from the cylindrical portion 73. ing. By housing such a lockup piston 71 in the pump shell 60, the pump shell 60 is divided into an apply chamber 75 and a release chamber 76. That is, an apply chamber 75 is defined on the turbine runner 63 side, and a release chamber 76 is defined on the front cover 72 side, with the lockup piston 71 as a boundary.

The aforementioned valve body 21 is connected to the torque converter 15 in order to supply hydraulic oil to the apply chamber 75 and the release chamber 76 . As shown in FIG. 5, the valve body 21 is provided with a clutch pressure control valve 80, a lockup control valve 81, and a flow rate control valve 82. A discharge oil passage 83 that guides hydraulic oil discharged from the oil pump 22 is connected to the clutch pressure control valve 80 . Further, a supply oil passage 84 through which hydraulic oil is supplied from the clutch pressure control valve 80 is connected to the lock-up control valve 81, and a discharge oil passage 85 through which hydraulic oil is discharged via the flow rate control valve 82 is connected. It is connected. Furthermore, an apply oil passage 86 communicating with the apply chamber 75 is connected to the lock-up control valve 81, and a release oil passage 87 communicating with the release chamber 76 is connected.

When the lockup clutch 70 is engaged, a spool valve shaft (not shown) of the lockup control valve 81, which is an oil passage switching valve, is controlled to the engagement position. As a result, the supply oil passage 84 and the apply oil passage 86 are connected via the lockup control valve 81, and the discharge oil passage 85 and the release oil passage 87 are connected via the lockup control valve 81. By controlling the lockup control valve 81 in this manner, hydraulic oil is supplied to the apply chamber 75 and is discharged from the release chamber 76, as shown by arrow FL1 in FIG. Then, when the pressure in the apply chamber 75 (hereinafter referred to as apply pressure) increases and the pressure in the release chamber 76 (hereinafter referred to as release pressure) decreases, the lockup piston 71 moves toward the front cover 72 due to the pressure difference. move in the direction closer to . As a result, the lockup piston 71 is pressed against the front cover 72, and the lockup clutch 70 is switched to the engaged state. That is, when the lockup clutch 70 is in the engaged state, the lockup piston 71 is engaged with the crankshaft 36 via the front cover 72.

On the other hand, when the lockup clutch 70 is released, the spool valve shaft of the lockup control valve 81 is controlled to the release position. As a result, the supply oil passage 84 and the release oil passage 87 are connected via the lockup control valve 81, and the discharge oil passage 85 and the apply oil passage 86 are connected via the lockup control valve 81. In this way, by controlling the lockup control valve 81, hydraulic oil is supplied to the release chamber 76 and hydraulic oil is discharged from the apply chamber 75, as shown by the arrow FL2 in FIG. 5. Then, when the apply pressure decreases and the release pressure increases, the pressure difference causes the lockup piston 71 to move in a direction away from the front cover 72. As a result, the lockup piston 71 is separated from the front cover 72, and the lockup clutch 70 is switched to the released state. The lockup clutch 70 can be switched depending on the vehicle speed. For example, when the vehicle speed exceeds a predetermined value, the lockup clutch 70 is switched to the engaged state, while when the vehicle speed is below the predetermined value, the lockup clutch 70 is switched to the released state.

[Lockup damper]
The torque converter 15 is provided with a lock-up damper (damper mechanism) 90. This lockup damper 90 is provided in a torque transmission path during engagement of the lockup clutch. Here, FIG. 6 is a diagram showing part of the lockup damper 90 and the lockup piston 71 along line AA in FIG. As shown in FIGS. 4 to 6, the lockup damper 90 has an outer plate 91 connected to the lockup piston 71. A plurality of grooves 92 are formed on the outer periphery of the outer plate 91, and a plurality of claws 93 are formed on the outer periphery of the lockup piston 71. By engaging the claw portion 93 of the lockup piston 71 with the groove portion 92 of the outer plate 91, the lockup piston 71 and the outer plate 91 are connected to each other.

The lock-up damper 90 also has an inner plate 94 that is connected to the turbine shaft 67 via the turbine hub 64. The turbine hub 64 and the inner plate 94 are connected to each other using a plurality of pin members 95. The lock-up damper 90 also has a plurality of coil springs 96, 97 that are arranged in the circumferential direction. One end of each of the coil springs 96, 97 contacts an inner convex portion 98 of the outer plate 91, and the other end of each of the coil springs 96, 97 contacts an outer convex portion 99 of the inner plate 94. In other words, the coil springs 96, 97 are provided between the outer plate 91 and the inner plate 94.

In this way, the inner plate 94 of the lockup damper 90 is connected to the turbine hub 64, and the outer plate 91 of the lockup damper 90 is connected to the lockup piston 71. That is, the lockup damper 90 is connected to both the turbine hub 64 and the lockup piston 71. As described above, the lockup damper 90 is provided in the torque transmission path during engagement of the lockup clutch. That is, when the lockup clutch 70 is switched to the engaged state, engine torque is transmitted from the front cover 72 to the lockup piston 71. Further, the engine torque transmitted to the lockup piston 71 is transmitted from the outer plate 91 of the lockup damper 90 to the inner plate 94 via the coil springs 96 and 97. The engine torque transmitted to the inner plate 94 of the lockup damper 90 is transmitted to the turbine shaft 67 via the turbine hub 64. In this way, while the lockup clutch is engaged, torque is transmitted between the crankshaft 36 and the turbine shaft 67 via the lockup damper 90.

Next, the operating state of the lockup damper 90 will be explained. FIG. 7 is a diagram showing an example of the operating status of the lockup damper 90. FIG. 7 shows a lockup damper 90 operating in a drive state, and also shows a lockup damper 90 operating in a coasting state. In addition, in FIGS. 6 and 7, in order to clarify the relative positions of the outer plate 91 and the inner plate 94, a virtual point Po is shown as a mark on the outer plate 91, and a virtual point Po is shown as a mark on the inner plate 94. A virtual point Pi is shown. Note that the arrow α shown in FIG. 7 is an arrow indicating the rotation direction of the outer plate 91 and the inner plate 94.

During accelerated driving, in which engine torque increases as the accelerator pedal is depressed, torque is transmitted from the crankshaft 36 to the turbine shaft 67. In other words, as shown by the arrow S1 in the drive state of FIG. precedes. In such a drive state of the lockup damper 90, the outer plate 91 rotates relative to the inner plate 94 toward the drive side, as shown by arrow Xd. That is, the lock-up damper 90 is twisted toward the drive side, and relative rotation between the outer plate 91 and the inner plate 94 is allowed.

On the other hand, during deceleration driving when the engine torque decreases as the accelerator pedal is released, torque is transmitted from the turbine shaft 67 to the crankshaft 36. In other words, as shown by the arrow S2 in the coasting state in FIG. precedes. In such a coasting state of the lockup damper 90, the outer plate 91 rotates relative to the inner plate 94 toward the coasting side opposite to the drive side, as shown by arrow Xc. That is, the lock-up damper 90 is twisted toward the coast side, and relative rotation between the outer plate 91 and the inner plate 94 is allowed.

[Wear between turbine hub and lock-up piston]
As described above, while the lock-up clutch is engaged, the lock-up damper 90 operates in the drive state or the coast state in response to engine torque fluctuations. In other words, the outer plate 91 and the inner plate 94 rotate relative to each other toward the drive side or the coast side in response to engine torque fluctuations. Here, the cylindrical portion 73 of the lock-up piston 71 is connected to the outer plate 91, and the hub portion 66 of the turbine hub 64 is connected to the inner plate 94. Therefore, when the outer plate 91 and the inner plate 94 rotate relative to each other, the hub portion 66 and the cylindrical portion 73 slidably supported by the hub portion 66 rotate relative to each other.

In this way, when the hub part 66 and the cylindrical part 73 rotate relative to each other, if the sliding surface pressure or sliding speed between the hub part 66 and the cylindrical part 73 increases excessively, the outer periphery of the hub part 66 There is a possibility that wear between the surface 66a and the inner circumferential surface 73a of the cylindrical portion 73 will progress. Promoting wear between the hub portion 66 and the cylindrical portion 73 is a factor that increases the gap between the hub portion 66 and the cylindrical portion 73 and causes the hydraulic oil to circulate, that is, the hydraulic oil is transferred from the apply chamber 75 to the release chamber 76. This is a factor that increases the amount of work of the oil pump 22 by causing the oil to flow. Further, the progress of wear between the hub portion 66 and the cylindrical portion 73 is a factor that causes hydraulic oil to flow from the apply chamber 75 to the release chamber 76, and is a factor that causes the lock-up clutch 70 to fail in engagement. Therefore, the control system 30 executes wear suppression control, which will be described later, in order to suppress the wear occurring in the hub portion 66 and the cylindrical portion 73.

[Wear suppression control]
FIG. 8 is a flowchart showing an example of an execution procedure of wear suppression control, and FIG. 9 is a diagram showing an example of sliding surface pressure P estimated based on engine speed and engine torque. 10 is a sectional view showing the sliding area between the hub part 66 and the cylindrical part 73 and its vicinity, and FIGS. 11 and 12 show the load input to the sliding part between the hub part 66 and the cylindrical part 73. It is a schematic diagram showing an example. Note that each step of the wear suppression control shown in FIG. 8 shows a process executed by the processor 50 that constitutes the control system 30. Furthermore, the wear suppression control shown in FIG. 8 is control that is executed by the control system 30 at predetermined intervals after the control system 30 is activated.

As shown in FIG. 8, in step S10, it is determined whether the lock-up clutch 70 is being engaged. If it is determined in step S10 that the lock-up clutch 70 is engaged, the process proceeds to step S11, and the sliding surface pressure P between the hub portion 66 and the cylindrical portion 73 is determined based on the engine rotation speed and engine torque. is estimated. That is, as shown in FIG. 9, the sliding surface pressure P is estimated to be higher as the engine speed becomes higher, and the sliding surface pressure P is estimated to be higher as the engine torque becomes larger. Here, the sliding surface pressure P is the surface pressure that acts on the sliding portion between the hub portion 66 and the cylindrical portion 73, and is the surface pressure determined based on the contact between two parallel cylinders according to Hertz's contact theory. In other words, the sliding surface pressure P is the radial load input to the sliding portion between the hub portion 66 and the cylindrical portion 73, the radius of curvature of the outer circumferential surface 66a of the hub portion 66, and the curvature of the inner circumferential surface 73a of the cylindrical portion 73. This is the surface pressure determined from Hertz's contact theory by using the radius, Poisson's ratio, Young's modulus, and the contact width between the hub portion 66 and the cylindrical portion 73. Note that, as the contact width between the hub portion 66 and the cylindrical portion 73, for example, as shown in FIG. The subtracted width (Wa-Wb) is used.

The first radial load W1 determined by the eccentricity of the rotating body assembly 101 including the lockup piston 71, the lockup damper 90, and the turbine runner 63 can be considered as the radial load input to the sliding portion. As shown in FIG. 11, when the center of gravity position G1 of the rotating body assembly 101 is deviated from the rotation center Ct, a first radial load W1 is generated in the rotating body assembly 101 in the radial direction. Further, the magnitude of the first radial load W1 is determined by the eccentricity and rotational speed of the rotating body assembly 101. Here, since the amount of eccentricity of the mass-produced rotor assembly 101 is within a predetermined design range, the control system 30 calculates the first radial load W1 based on the engine rotation speed, which is the rotation speed of the rotor assembly 101. It is possible to estimate. In other words, since the first radial load W1 increases as the engine speed increases, the control system 30 estimates the sliding surface pressure P to be higher as the engine speed increases.

In addition, as the radial load input to the sliding portion, a second radial load W2 determined by the variation of the coil springs 96, 97 constituting the lock-up damper 90 is considered. As shown in FIG. 12, if the spring force of the coil spring 97 varies, the second radial load W2 is generated in the radial direction of the inner plate 94. For example, if the spring force Fs1 of the coil spring 97a is greater than the spring force Fs2 of the other coil springs 97b, 97c, the balance of the spring forces acting on the inner plate 94 is lost, and the second radial load W2 is generated on the inner plate 94. Here, since the variation in the spring force of the mass-produced coil springs 96, 97 is within a predetermined design range, the control system 30 can estimate the second radial load W2 based on the engine torque that expands and contracts the coil springs 96, 97. In other words, the control system 30 estimates the sliding surface pressure P to be higher as the engine torque increases because the second radial load W2 increases as the engine torque increases.

8, in step S11, when the sliding surface pressure P is estimated based on the engine speed and engine torque, the process proceeds to step S12, where the sliding speed V between the hub portion 66 and the cylindrical portion 73 is estimated based on the rate of change of the engine torque. Here, FIG. 13 is a diagram showing an example of the relationship between the engine torque and the sliding speed V. As shown in FIG. 13, when the engine torque decreases (symbol a1), the absolute value of the rate of change of the engine torque (hereinafter referred to as the torque change speed) increases (symbol b1). In this way, when the engine torque decreases, the lock-up damper 90 is twisted to the coast side (symbol c1), and the absolute value of the twisting speed of the lock-up damper 90, that is, the absolute value of the sliding speed V between the hub portion 66 and the cylindrical portion 73 increases (symbol d1). Also, when the engine torque increases (symbol a2), the absolute value of the torque change speed increases (symbol b2). In this way, when the engine torque increases, the lock-up damper 90 is twisted toward the drive side (symbol c2), and the absolute value of the sliding speed V between the hub portion 66 and the cylindrical portion 73 increases (symbol d2). For this reason, the control system 30 estimates the sliding speed V to be higher as the torque change rate associated with the increase or decrease in engine torque increases.

As explained above, when the sliding surface pressure P is estimated in step S11 and the sliding speed V is estimated in step S12, the process proceeds to step S13, where the product of the sliding surface pressure P and the sliding speed V is calculated. A certain PV value is calculated. In subsequent step S14, it is determined whether the PV value exceeds a predetermined threshold value Xpv. If it is determined in step S14 that the PV value exceeds the threshold value Xpv, this means that the wear between the hub portion 66 and the cylindrical portion 73 is progressing significantly, so the process proceeds to step S15, and the torque change for the engine 12 is suppressed. Processing is executed. In other words, the sliding surface pressure P and the sliding speed V are high, which accelerates the wear between the hub portion 66 and the cylindrical portion 73, so the torque change suppression process that gently changes the engine torque is executed. Ru. On the other hand, if it is determined in step S14 that the PV value is less than or equal to the threshold value Xpv, the situation is such that wear between the hub portion 66 and the cylindrical portion 73 can be suppressed, so the torque change suppression process is not executed. Exit the routine.

[Torque change suppression processing]
FIG. 14 is a diagram showing an example of a threshold value Xpv to be compared with the PV value. As indicated by the symbol x1 in FIG. 14, in a region where the PV value exceeds the threshold value Xpv, the sliding surface pressure P and sliding speed V between the hub portion 66 and the cylindrical portion 73 are high, so the hub portion 66 and the cylindrical portion There is a possibility that wear with 73 will be accelerated. Therefore, when increasing or decreasing the engine torque under a situation where the PV value exceeds the threshold value Xpv, a torque change suppression process that gently changes the engine torque is executed. As will be described later, by executing the torque change suppression process, it is possible to suppress an excessive increase in the sliding speed V, and it is possible to suppress an excessive increase in the PV value. That is, as shown by the arrow β in FIG. 14, an excessive increase in the sliding speed V is suppressed so as to reduce the PV value.

FIG. 15 is a diagram showing an example of the execution status of the torque change suppression process. FIG. 15 shows a situation in which the PV value exceeds the threshold value Xpv in the process of decreasing engine torque. Further, in FIG. 15, the transition of engine torque, etc. when the torque change suppression process is executed as an example is shown by a solid line, and the transition of engine torque, etc. when the torque change suppression process is not executed as a comparative example. The transition is shown by a dashed line.

As shown by the solid line in FIG. 15, when the PV value exceeds the threshold value Xpv during the engine torque decrease process (symbol a1), the target decrease speed of the engine torque, i.e., the target change speed, is lowered from the first target speed Tv1 to the second target speed Tv2 (arrow b1). That is, when the PV value exceeds the threshold value Xpv, the target change speed of the engine torque is set lower than when the PV value is below the threshold value Xpv. Here, the first target speed Tv1 is the target change speed of the engine torque that is set when the PV value is equal to or less than the threshold value Xpv, and the second target speed Tv2 is the target change speed of the engine torque that is set when the PV value exceeds the threshold value Xpv. In this way, by lowering the target change speed to the second target speed Tv2 as the PV value increases, an excessive increase in the torque change speed can be suppressed (symbol c1), and the engine torque can be gradually reduced (symbol d1). This prevents an excessive increase in the sliding speed V (symbol e1) and an excessive increase in the PV value (symbol a2), thereby suppressing wear between the hub portion 66 and the cylindrical portion 73.

On the other hand, as shown by the broken line in FIG. 15, when the engine torque is decreased while maintaining the target rate of change at the first target speed Tv1, the rate of change in torque increases excessively (symbol f1) and the engine torque will rapidly decrease (symbol g1). In this case, since the sliding speed V increases excessively (symbol h1) and the PV value increases excessively (symbol i1), there is a risk that the wear between the hub portion 66 and the cylindrical portion 73 will progress. There is. As described above, the control system 30 sets the target rate of change of engine torque lower when the PV value exceeds the threshold Xpv than when the PV value is lower than the threshold Xpv. Thereby, it is possible to suppress an excessive increase in the sliding speed V, that is, an excessive increase in the PV value, and it is possible to suppress wear between the hub portion 66 and the cylindrical portion 73.

[Other embodiments]
In the above explanation, as a torque change suppression process, the target rate of change in engine torque is set low in the process of reducing engine torque, but this is not limiting, and the engine torque may be changed gradually using other control methods. You can let me. Here, FIG. 16 is a diagram showing other control examples 1 to 3 in the torque change suppression process. In FIG. 16, the solid line shows the engine torque transition when the torque change suppression process was executed as an example, and the broken line shows the engine torque transition when the torque change suppression process was not executed as a comparative example. It is shown.

As shown in FIG. 16 as control example 1, when the engine torque is reduced, the target reduction amount (target change amount) of the engine torque may be set small as a torque change suppression process. That is, when the PV value exceeds the threshold value Xpv during the reduction process of the engine torque, the target reduction amount of the engine torque may be reduced from the first target reduction amount T1a to the second target reduction amount T1b. That is, when the PV value exceeds the threshold value Xpv, the target reduction amount of the engine torque may be set smaller than when the PV value is below the threshold value Xpv. In this way, even when the target reduction amount of the engine torque is reduced with an increase in the PV value, the engine torque can be reduced gradually, so that an excessive increase in the sliding speed V, i.e., an excessive increase in the PV value, can be suppressed, and wear between the hub portion 66 and the cylindrical portion 73 can be suppressed. The first target reduction amount T1a is the target change amount of the engine torque that is set when the PV value is equal to or less than the threshold value Xpv, and the second target reduction amount T1b is the target change amount of the engine torque that is set when the PV value exceeds the threshold value Xpv.

As shown in FIG. 16 as control example 2, when the engine torque is increased, the target increase speed (target change speed) of the engine torque may be set low as a torque change suppression process. That is, when the PV value exceeds the threshold value Xpv during the increase process of the engine torque, the target increase speed of the engine torque may be lowered from the first target speed T2a to the second target speed T2b. That is, when the PV value exceeds the threshold value Xpv, the target increase speed of the engine torque may be set lower than when the PV value is below the threshold value Xpv. In this way, even when the target increase speed of the engine torque is lowered with the increase in the PV value, the engine torque can be increased gradually, so that an excessive increase in the sliding speed V, i.e., an excessive increase in the PV value, can be suppressed, and wear between the hub portion 66 and the cylindrical portion 73 can be suppressed. The first target speed T2a is the target change speed of the engine torque set when the PV value is equal to or lower than the threshold value Xpv, and the second target speed T2b is the target change speed of the engine torque set when the PV value exceeds the threshold value Xpv.

As shown in FIG. 16 as control example 3, when increasing the engine torque, the target increase amount (target change amount) of the engine torque may be set small as a torque change suppression process. That is, when the PV value exceeds the threshold value Xpv in the process of increasing the engine torque, the target increase amount of the engine torque may be reduced from the first target increase amount T3a to the second target increase amount T3b. That is, when the PV value exceeds the threshold value Xpv, the target increase amount of the engine torque may be set smaller than when the PV value is less than the threshold value Xpv. In this way, even if the target increase amount of engine torque is reduced as the PV value increases, the engine torque can be increased gradually, so that an excessive increase in the sliding speed V, that is, an increase in the PV value, can be prevented. Excessive rise can be suppressed, and wear between the hub portion 66 and the cylindrical portion 73 can be suppressed. Note that the first target increase amount T3a is the target change amount of engine torque that is set when the PV value is less than or equal to the threshold value Xpv, and the second target increase amount T3b is the target amount of change in engine torque that is set when the PV value is equal to or less than the threshold value Xpv. This is the target amount of change in engine torque set to .

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the gist of the present invention. For example, in the above description, the control system 30 is configured with three control units, but this is not limited to this, and the control system 30 may be configured with one control unit, or with two or four or more control units. Also, in the above description, the lock-up clutch 70 is engaged based on the vehicle speed, but this is not limited to this, and the lock-up clutch 70 may be engaged based on the vehicle speed and the required driving force.

In the above description, the torque change suppression process is executed immediately when the PV value exceeds the threshold value Xpv, but the present invention is not limited to this. For example, a count process may be executed each time the PV value exceeds the threshold value Xpv, and when the PV value exceeds the threshold value Xpv a predetermined number of times, the torque change suppression process may be executed. Further, in the above description, the threshold value Xpv, which is a fixed value, is used, but the present invention is not limited to this. For example, the threshold value Xpv may be changed based on the sliding speed V, or the threshold value Xpv may be changed based on the sliding surface pressure P. Note that when the engine control unit 28 calculates the engine torque, the engine torque may be calculated from the intake air amount or the fuel injection amount, or the engine torque may be calculated from the angular acceleration of the crankshaft 36. Alternatively, the engine torque may be calculated from the distortion of the rotating shaft by using a torque sensor that detects the distortion of the rotating shaft.

10 Vehicle control device 11 Vehicle 12 Engine 15 Torque converter 30 Control system 36 Crankshaft 50 Processor 51 Main memory (memory)
63 Turbine runner 64 Turbine hub 65 Flange portion 66 Hub portion 66a Outer peripheral surface 67 Turbine shaft 71 Lockup piston 73 Cylindrical portion 74 Disk portion 90 Lockup damper (damper mechanism)
P Sliding surface pressure V Sliding speed Xpv Threshold

Claims (5)

A vehicle control device installed in a vehicle,
a turbine hub including a flange portion connected to a turbine runner of a torque converter and a hub portion connected to a turbine shaft;
a lock-up piston comprising: a cylindrical portion slidably supported on an outer circumferential surface of the hub portion; and a disk portion extending radially outward from the cylindrical portion;
a damper mechanism that is connected to both the turbine hub and the lockup piston and allows relative rotation between the hub portion and the cylindrical portion;
a control system that controls an engine coupled to the torque converter, the control system including a processor and a memory communicatively connected to each other;
has
The control system includes:
Calculating a PV value, which is the product of sliding surface pressure and sliding speed between the hub part and the cylindrical part, in a state where the lock-up piston is fastened to the crankshaft of the engine,
When the PV value exceeds a threshold value, the engine torque is changed more gently than when the PV value is less than the threshold value.
Vehicle control device. The vehicle control device according to claim 1,
The control system includes:
Estimating the sliding surface pressure based on engine speed and engine torque,
estimating the sliding speed based on the rate of change of engine torque;
Vehicle control device. The vehicle control device according to claim 2,
The control system includes:
The higher the engine speed, the higher the sliding surface pressure is estimated,
The greater the engine torque, the higher the sliding surface pressure is estimated,
The sliding speed is estimated to be higher as the rate of change of engine torque becomes higher;
Vehicle control device. The vehicle control device according to any one of claims 1 to 3,
The control system includes:
When the PV value is greater than the threshold value, the target change rate of the engine torque is set lower than when the PV value is less than the threshold value.
Vehicle control device. In the vehicle control device according to any one of claims 1 to 3,
The control system includes:
When the PV value exceeds the threshold value, setting a target change amount of engine torque smaller than when the PV value is less than the threshold value.
Vehicle control device.

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